This was started as a phase I/II study to determine the safety and, if possible, the effectiveness of IFN-gamma in treating patients with NTM pulmonary infections that had progressed despite aggressive, multi-drug, antimycobacterial therapy. Patient entry into this protocol has been completed, and analysis of the data is in progress. Part of the original aggreement with patients entering the study was that they would be able to continue IFN-gamma, along with the most effective antibiotics, if they were experiencing benefit from IFN-gamma therapy. We are currently in that continuation phase of the protocol. Twenty-five patients were entered into this study. IFN-gamma therapy has been stopped for 16 of these patients for various reasons. At present, nine patients continue IFN-gamma therapy since their NJC physicians have concluded that this therapy has resulted in improvement of their disease or are currently trying to determine if this is the case.